Temporary roof support system with anti-rotation feature

ABSTRACT

A temporary roof support system with an anti-rotation feature is provided. The temporary roof support system includes a base, a multistage hydraulic cylinder, a multistage telescopic cover assembly and a locking tube assembly. The multistage telescopic cover assembly encompasses the multistage hydraulic cylinder, and includes a first plurality of cylinders of successively differing diameters disposed coaxially. The locking, tube assembly includes a second plurality of cylinders disposed coaxially and of successively differing diameters including an outermost cylinder and an innermost cylinder. The second pivot end of the locking tube assembly is coupled to the crossbar and the first pivot end of the locking tube assembly is coupled to the base, and a length of the locking tube assembly is parallel to the vertical axis.

TECHNICAL FIELD

The present disclosure relates to a temporary roof support system for aroof bolter machine, and more particularly, to a temporary roof supportsystem including a locking tube assembly to prevent rotation of the roofsupport system during operation.

BACKGROUND

Roof bolting is a common process to stabilize roofs in underground coalmines and tunnels. It involves inserting conventional, cable or resinbolts by drilling directly into the rock strata using a roof boltermachine. The roof bolter machine generally includes a temporary roofsupport system for installing multiple bolts simultaneously in a roof tomake it self-supporting. Typically, the temporary roof support systemincludes a crossbar mounted on a hydraulic cylinder. The crossbar hasrocker pads at either end to support the roof while drilling holes inthe rock strata, and subsequently introducing bolts in these holes. Thehydraulic cylinder not only provides enough pressure to lift thecrossbar but to support the temporary roof support system as well.

When the hydraulic cylinder is pressurized to lift the crossbar, thehydraulic cylinder develops an inherent rotary motion. This rotarymotion tends to undesirably rotate the crossbar, which subsequentlychanges position of the rocker pads. Currently, rectangular multistagecovers are used to prevent the rotation of the crossbar due to lockingby diagonals of the rectangular multistage covers. Consequently, therectangular multistage covers have to be very heavy and thick, in orderto provide necessary force for preventing the rotation of the cylinder.This adds excess weight to the temporary roof support system.

U.S. Pat. No. 4,284,368 discloses a temporary support system for a mineroof. The temporary support system includes a base, a telescopic columnmounted on the base, and a crossbar connected to the top of the column.The system further includes two expandable hydraulic jacks, eachhydraulic jack mounted on each side of the column. One end of each ofthe jacks is connected to the base and the other end of each of thejacks is connected to the crossbar for expanding and retracting thetemporary roof support system. Though, the temporary support systemprevents the rotation of the crossbar, the temporary support system usesmultiple jacks, which adds complexity to the system. Also, the jacks aresingle stage hydraulic cylinders, which are used to operate the sameactuator, and are needed to be operated in unison otherwise they tend topull and push each other, in turn, leading to in efficient operation ofthe temporary roof support system. Moreover, a difference in minimumheight of the crossbar and the maximum height of the crossbar isdependent on stroke length of the jacks. Since jacks are single stagehydraulic cylinders, the difference and thus, the height to which thecrossbar can be raised is limited. Thus, there exists a need of asimpler design with less number of components for the temporary roofsupport system to restrict the undesirable rotation of the crossbar.

SUMMARY OF THE INVENTION

In one aspect of the present disclosure, a temporary roof support systemis provided. The temporary roof support system includes a base, amultistage hydraulic cylinder, a multistage telescopic cover assembly, acrossbar and a locking tube assembly. The multistage hydraulic cylinderhas a first end and a second end, and multistage hydraulic cylinder ismounted on the base at the first end. The multistage hydraulic cylinderis extendable along a vertical axis. The multistage telescopic coverassembly encompasses the multistage hydraulic cylinder, and is coupledto the multistage hydraulic cylinder at the second end. The multistagetelescopic cover assembly further includes a first plurality ofcylinders of successively differing diameters disposed coaxially withinthe multistage telescopic cover assembly. The multistage hydrauliccylinder is coupled to the crossbar at the second end using a pivotjoint at a center of the crossbar. Further, the locking tube assemblyhas a first pivot end and a second pivot end. The locking tube assemblyincludes a second plurality of cylinders including an outermost cylinderand an innermost cylinder. The second plurality of cylinders iscoaxially disposed and having successively differing diameters. Thelocking tube assembly further includes a first mounting eye at the firstpivot end and a pair of mounting eyes at the second pivot end. The firstmounting eye is coupled to the innermost cylinder of the locking tubeassembly and the pair of mounting eyes is coupled to the outermostcylinder of the locking tube assembly. The second pivot end of thelocking tube assembly is coupled to the crossbar and the first pivot endof the locking tube assembly is coupled to the base such that a lengthof the locking tube assembly is parallel to the vertical axis.

Other features and aspects of this disclosure will be apparent from thefollowing description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a roof bolter having a temporary roofsupport system shown in accordance with the concepts of the presentdisclosure;

FIG. 2 is a perspective view of the temporary roof support system inaccordance with the concepts of the present disclosure;

FIG. 3 is a side view of the temporary roof support system in accordancewith the concepts of the present disclosure;

FIG. 4 is a front sectional view of the temporary roof support systemtaken along 4-4′ of FIG. 2, and a broken view of a locking tube assemblyof the temporary roof support system in accordance with the concepts ofthe present disclosure; and

FIG. 5 is a front view of the temporary roof support system in anextended position in accordance with the concepts of the presentdisclosure.

DETAILED DESCRIPTION

Referring to FIG. 1, a roof bolter machine 10 includes a rear frame 12,a main frame 14, a drilling station 16, a drilling boom 18 and atemporary roof support system 20. The roof bolter machine 10 includesother components such as a prime mover like electric motor or engine,wheels, boom cylinder, stage cylinder etc. For the purpose ofsimplicity, various other components of the roof bolter machine 10 arenot labeled in FIG. 1, The temporary roof support system 20 is used forinstalling multiple bolts in a roof to make the roof self supporting.The temporary roof support system 20 includes a base 22, a multistagetelescopic cover assembly 24, a crossbar 26 with rocker pads 28. Duringa roof bolting operation by the roof bolter machine 10, the rocker pads28 at either end of the crossbar 26 support the roof while bolts areinstalled in the roof.

Referring to FIG. 2 and FIG. 3, the temporary roof support system 20includes the base 22 and the multistage telescopic cover assembly 24which is extendable along a vertical axis 1-1′. The crossbar 26 iscoupled to a multistage hydraulic cylinder (not shown) at a center ofthe crossbar 26 using a pivot joint 30. The temporary roof supportsystem 20 further includes a locking tube assembly 32 having a firstpivot end 34 and a second pivot end 36. The first pivot end 34 of thelocking tube assembly 32 has a first mounting eye 38 and the secondpivot end 36 of the locking tube assembly 32 has a pair of mounting eyes40. The second pivot end 36 of the locking tube assembly 32 is coupledto a first mounting bracket 42 of the crossbar 26 using the pair ofmounting eyes 40 and the first pivot end 34 of the locking tube assembly32 is coupled to a second mounting bracket 44 of the base 22 using thefirst mounting eye 38. The locking tube assembly 32 is coupled to thefirst mounting bracket 42 of the crossbar 26, and the second mountingbracket 44 of the base 22 using pins 46. A length L₁ of the locking tubeassembly 32 is parallel to the vertical axis 1-1.

Referring to FIG. 4, the multistage telescopic cover assembly 24encompasses a multistage hydraulic cylinder 48. The multistage hydrauliccylinder 48 has a first end 50 and a second end 52, and is extendablealong the vertical axis in order to lift the crossbar 26. The multistagehydraulic cylinder 48 is mounted on the base 22 at the first end 50 andis coupled to the multistage telescopic cover assembly 24 at the secondend 52. The multistage telescopic cover assembly 24 includes a firstplurality of cylinders 54 of successively differing diameters disposedcoaxially within the multistage telescopic cover assembly 24. The firstplurality of cylinders 54 includes an outermost cylinder 56, which isused to couple the multistage telescopic cover assembly 24 to themultistage hydraulic cylinder 48 at the second end 52. Further, thecrossbar 26 is coupled to the multistage hydraulic cylinder 48 at thesecond end 52 of the multistage hydraulic cylinder 48. The crossbar 26is coupled to the multistage hydraulic cylinder 48 using the pivot joint30 at a center of the crossbar 26.

Further, the locking tube assembly 32 includes a second plurality ofcylinders 58 including an outermost cylinder 60 and an innermostcylinder 62, the second plurality of cylinders 58 are coaxially disposedwithin the locking tube assembly 32 and have successively differingdiameters. The first mounting eye 38 is coupled to the innermostcylinder 62 of the locking tube assembly 32. The pair of mounting eyes40 is coupled to the outermost cylinder 60 of the locking tube assembly32. The locking tube assembly 32 has the length L₁. When the multistagehydraulic cylinder 48 is extended along the vertical axis 1-1′, thesecond plurality of cylinders 58 of the locking tube assembly 32 alsoextends along the length L₁ such that the length L₁ of the locking tubeassembly 32 is parallel to the vertical axis 1-1′. Since the first pivotend 34 of the locking tube assembly 32 is connected to the base 22, thelocking tube assembly 32 can only extend and contract along the lengthL₁, but can't rotate about axis 1-1′. Thus it allows the crossbar 26along with the multistage telescopic cover assembly 24 to lift up anddown but arrests its inherent rotation alone.

Referring to FIG. 5, the temporary roof support system 20 is in anextended position. In order to support a roof during roof boltingprocess, the crossbar 26 is raised to support the roof using themultistage hydraulic cylinder 48 along the vertical axis 1-1′. Due tothe extension of the multistage hydraulic cylinder 48, the multistagetelescopic cover assembly 24 and the locking tube assembly 32 areextended along with the vertical axis 1-1′ such that the length L₁ ofthe locking tube assembly 32 is parallel to the vertical axis 1-1′. Thecrossbar 26 is coupled to the multistage hydraulic cylinder 48 via thepivot joint 30. The rocker pads 28 are mounted on each end of thecrossbar 26 for engagement with the roof when the multistage telescopichydraulic cylinder 48 is raised.

When the crossbar 26 supports uneven roof levels at both sides, thecrossbar 26 needs to be inclined at an angle to the horizontal. At thisstage, the pins 46 allows the locking tube assembly 32 to adjust thisdeflection on its own by extending and contracting of the locking tubeassembly 32, and by pivoting of the first pivot end 34 and the secondpivot end 36 of the locking tube assembly 32. This key movement allowsthe locking tube assembly 32 to adjust its vertical orientation. Thus,the crossbar 26 is able to freely rotate along the axis of the pivotjoint 30.

INDUSTRIAL APPLICABILITY

Roof bolting is a common process to stabilize roofs in underground coalmines and tunnels using a roof bolter machine. The roof bolter machinegenerally includes a temporary roof support system for installingmultiple bolts simultaneously in a roof to make it self-supporting.Typically, the temporary roof support system includes a crossbar mountedon a hydraulic cylinder. The crossbar has rocker pads at either end tosupport the roof while drilling holes in the rock strata, andsubsequently introducing bolts in these holes. When the hydrauliccylinder is pressurized to lift the crossbar, the hydraulic cylinderdevelops an inherent rotary motion. This rotary motion tends toundesirably rotate the crossbar, which subsequently changes position ofthe rocker pads. To prevent the rotation of the crossbar, rectangularmultistage covers are used. However, such rectangular covers add anexcess weight and a lot of complexity into the temporary roof supportsystem.

Referring to FIG. 2, the present disclosure provides the temporary roofsupport system 20 including the locking tube assembly 32. The lockingtube assembly 32 is coupled to the crossbar 26 and the base 22. As themultistage hydraulic cylinder 48 is extended along the vertical axis1-1′, the locking tube assembly 32 extends along with the multistagehydraulic cylinder 48 and prevents the rotation of the crossbar 26 alongthe vertical axis 1-1′. The locking tube assembly 32 is coupled to thebase 22 using the first mounting eye 38, and is coupled to the crossbar26 using the pair of mounting eyes 40. The first mounting eye 38 and thepair of mounting eyes 40 each form a pivot joint with the base 22 andthe crossbar 26 respectively, in order to allow swinging of the crossbar26 along the axis of the pivot joint 30. Thus, the locking tube assembly32 allows the crossbar 26 to raise, lower, swing about the pivot joint30.

Further, the temporary roof support system 20 does not require themultistage telescopic cover assembly 24 to prevent the rotation of themultistage hydraulic cylinder 48, therefore, the multistage telescopiccover assembly 24 need not be rectangular in design. Also, as themultistage telescopic cover assembly 24 does not need to preventrotation of the crossbar 26, the multistage telescopic cover assembly 24is light in weight, reducing the overall weight of the roof supportsystem 20. Also, the multistage telescopic cover assembly 24 iscylindrical in design, therefore, there is very less rubbing actionbetween the first plurality of cylinders 54 of the multistage coverassembly 24, thereby, very less friction is generated. Consequently, theneed for lubrication and use of wear pads are not required, therebyreducing the overall manufacturing costs of the roof bolter machine 10.

Further, in an extended position of the multistage cover assembly 24,the outermost cylinder 56 covers a top of the inner cylinders, leavingno space for the debris to enter the multistage cover assembly 24. Theoutermost cylinder 56 of the multistage telescopic cover assembly 24 iscoupled to the crossbar 26 via the pivot joint 30. Due to this design ofthe multistage telescopic cover assembly 24, there are less chances ofdirt to stick and retain in the cylindrical covers and thereby, themaintenance requirements are reduced and consequently, idle time of theroof bolter machine 10 is reduced.

While aspects of the present disclosure have been particularly shown anddescribed with reference to the embodiments above, it will be understoodby those skilled in the art that various additional embodiments may becontemplated by the modification of the disclosed machines, systems andmethods without departing from the spirit and scope of what isdisclosed. Such embodiments should be understood to fall within thescope of the present disclosure as determined based upon the claims andany equivalents thereof.

What is claimed is:
 1. A temporary roof support system for a roof boltermachine, the temporary roof support system comprising: a base; amultistage hydraulic cylinder having a first end and a second end, themultistage hydraulic cylinder mounted on the base at the first end, themultistage hydraulic cylinder extendable along a vertical axis; amultistage telescopic cover assembly encompassing the multistagehydraulic cylinder, and coupled to the multistage hydraulic cylinder atthe second end, the multistage telescopic cover having a first pluralityof cylinders of successively differing diameters disposed coaxiallywithin the multistage telescopic cover; a crossbar coupled to themultistage hydraulic cylinder at the second end, the crossbar coupled tothe multistage hydraulic cylinder at a center of the crossbar using apivot joint; a locking tube assembly having a first pivot end and asecond pivot end, the locking tube assembly including: a secondplurality of cylinders including an outermost cylinder and an innermostcylinder, the second plurality of cylinders being coaxially disposed andhaving successively differing diameters; a first mounting eye at thefirst pivot end, the first mounting eye coupled to the innermostcylinder; a pair of mounting eyes at the second pivot end, the pair ofmounting eyes coupled to the outermost cylinder; wherein the secondpivot end of the locking tube assembly is coupled to the crossbar andthe first pivot end of the locking tube assembly is coupled to the base,and wherein a length of the locking tube assembly being parallel to thevertical axis.